This invention relates to an applicator to which a highly viscous fluid to be applied such as correction fluid and make-up fluid is charged.
Most of such applicators have an application member attached to the tip of a fluid tank molded using a flexible material and a valve mechanism disposed behind the application member. When the applicator is used, the tip of the application member is pressed against a surface to be treated to open the valve, and in this state the fluid tank is pressed to squeeze out a highly viscous fluid such as correction fluid therefrom and feed it to the application member. When the application member is of a spherical form, it is housed in a stem having a tubular form whose tip is caulked in such a way that the ball may partly be exposed from the tip of the stem and pushed outward by the outer end of a movable piece resiliently urged by a spring. In other words, when the applicator is not used, the spherical application member or ball is brought into intimate contact with the inner caulked edge of the stem, and thus these members constituting a valve structure are designed not to discharge the fluid in this state.
When the ball is pressed against the surface to be treated for application in such type of applicator, the ball is retracted from the inner caulked edge of the stem to assume an open valve structure. However, since the stem has a tubular form, the ball is fully embedded therein if the applicator is pressed strongly against the surface to be treated. Accordingly, the valve structure remains wide open to discharge the fluid excessively. Namely, the discharge varies depending on the pressure applied to the surface to be treated, making it difficult to control discharge of the fluid.
While the ball rolls in contact with the outer end face of the movable piece resiliently urged by the spring, the contact area is narrow and the movable piece is unstable since it is resiliently urged by the spring to be movable. Accordingly, the ball does not roll smoothly, making the application procedure difficult.